Fox News has learned from sources who were on the ground in Benghazi that an urgent request from the CIA annex for military back-up during the attack on the U.S. Consulate and subsequent attack several hours later was denied by officials in the CIA chain of command -- who also told the CIA operators twice to "stand down" rather than help the ambassador's team when shots were heard at approximately 9:40 p.m. in Benghazi on Sept. 11.

In the aftermath of the attack on the U.S. embassy in Libya, which left
the ambassador and three other Americans dead, the Obama Administration
is receiving growing criticism of how it handled the situation.

Sources tell Fox News that U.S. intelligence officials knew within 24 hours of the assault on the U.S. Consulate in Libya that it was a terrorist attack and suspected Al Qaeda-tied elements were involved.